My code is
\[
D_{k+1}(x_{k+1}) = \min_{\begin{array}{c}
\text{all } x_k \text{ such that}\\
p_{{x_k}{x_{k+1}}} > 0
\end{array}}
\left[ D_k(x_k)-\ln\left(p_{{x_{k-1}}{x_k}}
r\left(z_k; x_{k-1}, x_k\right)\right) \right]
\]
However, I want to make all x_k such that p_{{x_k}{x_{k+1}} > 0
smaller.
How can I reduce the size of that part?
\resizebox
or\scalebox
probably from thegraphicx
package. I would also suggest\forall x_k|p_{{x_k}{x_{k+1}}}